SCHIZOPHRENIA
Diagnosis and classification:
SCHIZOPHRENIA – characterised by a
profound disruption of cognition and
emotion which affects language, thought,
perception and sense of self
CLASSIFICATION OF MENTAL DISORDER –
the process of organizing symptoms into
categories based on which symptoms
cluster together in sufferers
DSM-5 classification – one positive symptom must be present
(delusions, hallucinations or speech disorganization)
ICD-10 classification – two or more negative symptoms are
sufficient for diagnosis (eg. avolition and speech poverty)
POSITIVE SYMPTOMS – atypical symptoms experienced in addition to
normal experiences, include hallucinations and delusions
NEGATIVE SYMPTOMS – atypical symptoms that represent the loss of a
usual experience, include speech poverty and avolition
Symptoms:
HALLUCINATIONS – (positive symptom) sensory
experiences of stimuli that have either no basis in
reality or are distorted perceptions of real things,
auditory (hearing voices) or visual (seeing things)
DELUSIONS – (positive symptom) beliefs that have
no basis in reality, make the sufferer behave in
ways that make sense to them but are bizarre to others, delusions of
grandeur, delusions of control or delusions of persecution
AVOLITION – (negative symptom) severe loss of motivation to carry out
everyday tasks (eg. work, hobbies, personal care), results in lowered
activity levels and unwillingness to carry out goal-oriented behaviours
, SPEECH POVERTY – (negative symptom) a reduction in the amount and
quality of speech, may include a delay in verbal responses during
conversation, DSM emphasises speech disorganization and incoherence
MOOD DISTURBANCES – eg. affective flattening
Evaluation:
RELIABILITY – consistency, inter-rater reliability (the extent to which two or
more mental health professionals arrive at the same diagnosis for the same
patients), Elie Cheniaux et al (2009), two psychiatrists independently
diagnosed 100 patients using DSM and ICD criteria and inter-rater reliability
was poor which is a weakness of the diagnosis of schizophrenia (one had
26 diagnosed according to DSM and 44 according to ICD, the other had 13
according to DSM and 24 according to ICD)
VALIDITY – assess validity using criterion validity; do different assessment
systems arrive at the same diagnosis for the same patient, stats from
Cheniaux et al. show that Sz is more likely to be diagnosed using ICD so it
is either over-diagnosed by ICD or under-diagnosed by DSM, either is a
weakness of diagnosis
CO-MORBIDITY – if conditions occur together
frequently validity of diagnosis and
classification can be questioned as they may be
a single condition, Buckley et al (2009) found
that 50% of patients with Sz are also diagnosed
with depression or substance abuse (47%),
PTSD occurred with 29% of cases and OCD with 23%, it may be that Sz and
depression are better seen as a single condition, which is a weakness of
diagnosis and classification due to the confusion
SYMPTOM OVERLAP – Sz and bipolar both have positive symptoms like
delusions and negative symptoms like avolition, which calls into question
the validity of diagnosis/classification of Sz. Under ICD a patient may be
diagnosed with Sz but the same patient may be diagnosed with bipolar
disorder under DSM
GENDER BIAS – Longenecker et al. (2010) concluded that since the 1980s
men have been diagnosed with Sz more often than women, may be
because men are more genetically vulnerable, or that there is gender bias
2
Diagnosis and classification:
SCHIZOPHRENIA – characterised by a
profound disruption of cognition and
emotion which affects language, thought,
perception and sense of self
CLASSIFICATION OF MENTAL DISORDER –
the process of organizing symptoms into
categories based on which symptoms
cluster together in sufferers
DSM-5 classification – one positive symptom must be present
(delusions, hallucinations or speech disorganization)
ICD-10 classification – two or more negative symptoms are
sufficient for diagnosis (eg. avolition and speech poverty)
POSITIVE SYMPTOMS – atypical symptoms experienced in addition to
normal experiences, include hallucinations and delusions
NEGATIVE SYMPTOMS – atypical symptoms that represent the loss of a
usual experience, include speech poverty and avolition
Symptoms:
HALLUCINATIONS – (positive symptom) sensory
experiences of stimuli that have either no basis in
reality or are distorted perceptions of real things,
auditory (hearing voices) or visual (seeing things)
DELUSIONS – (positive symptom) beliefs that have
no basis in reality, make the sufferer behave in
ways that make sense to them but are bizarre to others, delusions of
grandeur, delusions of control or delusions of persecution
AVOLITION – (negative symptom) severe loss of motivation to carry out
everyday tasks (eg. work, hobbies, personal care), results in lowered
activity levels and unwillingness to carry out goal-oriented behaviours
, SPEECH POVERTY – (negative symptom) a reduction in the amount and
quality of speech, may include a delay in verbal responses during
conversation, DSM emphasises speech disorganization and incoherence
MOOD DISTURBANCES – eg. affective flattening
Evaluation:
RELIABILITY – consistency, inter-rater reliability (the extent to which two or
more mental health professionals arrive at the same diagnosis for the same
patients), Elie Cheniaux et al (2009), two psychiatrists independently
diagnosed 100 patients using DSM and ICD criteria and inter-rater reliability
was poor which is a weakness of the diagnosis of schizophrenia (one had
26 diagnosed according to DSM and 44 according to ICD, the other had 13
according to DSM and 24 according to ICD)
VALIDITY – assess validity using criterion validity; do different assessment
systems arrive at the same diagnosis for the same patient, stats from
Cheniaux et al. show that Sz is more likely to be diagnosed using ICD so it
is either over-diagnosed by ICD or under-diagnosed by DSM, either is a
weakness of diagnosis
CO-MORBIDITY – if conditions occur together
frequently validity of diagnosis and
classification can be questioned as they may be
a single condition, Buckley et al (2009) found
that 50% of patients with Sz are also diagnosed
with depression or substance abuse (47%),
PTSD occurred with 29% of cases and OCD with 23%, it may be that Sz and
depression are better seen as a single condition, which is a weakness of
diagnosis and classification due to the confusion
SYMPTOM OVERLAP – Sz and bipolar both have positive symptoms like
delusions and negative symptoms like avolition, which calls into question
the validity of diagnosis/classification of Sz. Under ICD a patient may be
diagnosed with Sz but the same patient may be diagnosed with bipolar
disorder under DSM
GENDER BIAS – Longenecker et al. (2010) concluded that since the 1980s
men have been diagnosed with Sz more often than women, may be
because men are more genetically vulnerable, or that there is gender bias
2
